package de.fub.bytecode.classfile;

import java.io.*;

/**
 * This class represents the method info structure, i.e. the representation 
 * for a method in the class. See JVM specification for details.
 * A method has access flags, a name, a signature and a number of attributes.
 *
 * @version $Id: Method.java,v 1.1.1.1 2000/08/10 16:05:07 cvs Exp $
 * @author  <A HREF="http://www.inf.fu-berlin.de/~dahm">M. Dahm</A>
 */
public final class Method extends FieldOrMethod {
  /**
   * Empty constructor, all attributes have to be defined via `setXXX'
   * methods. Use at your own risk.
   */
  public Method() {}  
  /**
   * @param access_flags Access rights of method
   * @param name_index Points to field name in constant pool
   * @param signature_index Points to encoded signature
   * @param attributes Collection of attributes
   * @param constant_pool Array of constants
   */
  public Method(int access_flags, int name_index, int signature_index,
		Attribute[] attributes, ConstantPool constant_pool)
  {
	super(access_flags, name_index, signature_index, attributes, constant_pool);
  }  
  /**
   * Initialize from another object. Note that both objects use the same
   * references (shallow copy). Use clone() for a physical copy.
   */
  public Method(Method c) {
	super(c);
  }  
  /**
   * Construct object from file stream.
   * @param file Input stream
   * @throw IOException
   * @throw ClassFormatError
   */
  Method(DataInputStream file, ConstantPool constant_pool)
	   throws IOException, ClassFormatError
  {
	super(file, constant_pool);
  }  
  /**
   * Called by objects that are traversing the nodes of the tree implicitely
   * defined by the contents of a Java class. I.e., the hierarchy of methods,
   * fields, attributes, etc. spawns a tree of objects.
   *
   * @param v Visitor object
   */
  public void accept(Visitor v) {
	v.visitMethod(this);
  }  
  /**
   * @return deep copy of this method
   */
  public final Method copy(ConstantPool constant_pool) {
	return (Method)copy_(constant_pool);
  }  
  /**
   * @return Code attribute of method, if any
   */   
  public final Code getCode() {
	for(int i=0; i < attributes_count; i++)
	  if(attributes[i] instanceof Code)
	return (Code)attributes[i];

	return null;
  }  
  /**
   * @return ExceptionTable attribute of method, if any, i.e. list all
   * exceptions the method may throw not exception handlers!
   */
  public final ExceptionTable getExceptionTable() {
	for(int i=0; i < attributes_count; i++)
	  if(attributes[i] instanceof ExceptionTable)
	return (ExceptionTable)attributes[i];

	return null;
  }  
  /**
   * Return string representation close to declaration format,
   * `public static int main(String[]) throws IOException', e.g.
   *
   * @return String representation of the method.
   */
  public final String toString() {
	ConstantUtf8  c;
	ConstantValue cv;
	String        name, signature, access; // Short cuts to constant pool
	String        exceptions;
	StringBuffer  buf;
	Attribute[]   attr;

	access = Utility.accessToString(access_flags);

	// Get name and signature from constant pool
	c = (ConstantUtf8)constant_pool.getConstant(signature_index, 
						CONSTANT_Utf8);
	signature = c.getBytes();

	c = (ConstantUtf8)constant_pool.getConstant(name_index, CONSTANT_Utf8);
	name = c.getBytes();

	signature = Utility.methodSignatureToString(signature, name, access);

	buf = new StringBuffer(signature);

	for(int i=0; i < attributes_count; i++) {
	  Attribute a = attributes[i];

	  if(!((a instanceof Code) || (a instanceof ExceptionTable)))
	buf.append(" <" + a.toString() + ">");
	}

	ExceptionTable e = getExceptionTable();
	if(e != null) {
	  String str = e.toString();
	  if(!str.equals(""))
	buf.append("\n\t\tthrows " + str);
	}
 
	return buf.toString();
  }  
}